1. Technical Field
The present disclosure relates to a backlight assembly, and more particularly, to a backlight assembly having a structure for enhancing lamp efficiency and a liquid crystal display having the same.
2. Discussion of the Related Art
Liquid crystal displays (LCDs) are widely used because of their lightweight, thin, low-power drive, full color and high resolution characteristics. LCDs are currently used in connection with devices such as, personal computers, notebook computers, PDAs, telephones, televisions, and audio/video devices. LCDs adjust an amount of light transmitted in accordance with image signals applied to a number of control switches arrayed in a matrix and then display a desired image on an LCD panel.
To this end, the LCD comprises an LCD panel on which images are displayed, an LCD drive integrated circuit (IC) for operating the LCD panel, a backlight unit used as a light source of the LCD, and a chassis used to fasten respective components of the LCD thereto. The backlight unit is classified into a direct type in which a light source is disposed at a surface of a panel to illuminate an entire surface of the panel and an edge type in which line light sources are disposed at one or more sides of a panel to reflect and diffuse light on, for example, a light guide plate, and a reflection plate.
FIG. 1 is an exploded perspective view of an LCD, and FIG. 2 is a schematic sectional view of the LCD shown in FIG. 1.
Referring to FIG. 1, a backlight unit is laminated on an LCD panel 5 in which a thin film transistor substrate with a plurality of pixels formed in a matrix and a color filter substrate with R, G and B color filters formed in a matrix are bonded with each other. The combined backlight unit and LCD panel are secured in a mold frame. A gate printed circuit board 7 for the application of driving signals is connected through a flexible printed circuit board at one side of the LCD panel 5. The gate printed circuit board 7 is interposed between a gate pad and gate TCP (Taped Carrier Package) of the LCD panel 5, and a data printed circuit 9 for the application of data signals is connected with a data pad through the flexible printed circuit board at the other side of the LCD panel 5. Under a bottom of the LCD panel 5 is sequentially laminated a plurality of optical sheets 11, a lamp 13, a light guide plate 15 and a reflection plate 17, which form the backlight unit 10. The lamp 13 serves as a light source of the backlight unit 10. The light guide plate 15 emits light generated from the lamp 13 toward the LCD panel 5 and a reflection plate 17 reflects light leaked from the light guide plate 15 toward the LCD panel 5 to enhance light efficiency.
The backlight unit and the LCD panel are inserted in the mold frame 21 such that they can be protected from an external impact and also optically aligned. Top and bottom chassis 1 and 22 are fastened to the top and bottom of the mold frame, respectively, to protect the LCD panel and the backlight unit from external impact.
Referring to FIG. 2, the backlight unit 10 composed of the plurality of optical sheets 11, the light guide plate 15, the reflection plate 17 and the lamp 13 is contained in the mold frame 21, and the lamp 13 is fixed to a lamp reflector 30.
The lamp 13 is installed at one side of the light guide plate 15, and the lamp reflector 30 is used to fix the lamp 13 thereto. Further, an inner surface of the lamp reflector 30 is coated with metal to increase its reflection factor. As a result, light propagating in a direction away from the light guide plate 15 can be reflected to a direction toward the light guide plate 15 so as to be incident on the side of the light guide plate 15. In addition, light that leaks from the light guide plate 15 and then propagates downwards is reflected toward the LCD panel by means of the reflection plate 17 disposed below the light guide plate 15.
Since the lamp reflector 30 includes a metallic material and is arranged in a longitudinal direction of the lamp such that it can fix the lamp, the light guide plate and reflection plate thereto, the lamp reflector 30 has a high weight. Thus, it is difficult to make an LCD that includes the lamp reflector 30 thin and lightweight. Further, when operating the LCD lamp, heat generated from the lamp is not easily released to the outside due to the lamp reflector 30. Therefore, it is also difficult to maintain a lamp temperature at which lamp efficiency can be maximized.